The present invention generally relates to wafer processing tooling on a wafer processing line in a semiconductor processing plant and, more particularly, to providing flexibility to wafer processing by reconfiguring portions of the line whenever necessary.
A conventional semiconductor processing plant typically includes multiple processing areas or bays interconnected by a path, such as a conveyor belt. Each bay generally includes the requisite processing tools (interconnected by a subpath) to process semiconductor wafers for a particular purpose, such as photolithography, chemical-mechanical polishing or chemical vapor deposition, for example. Material stockers or stocking tools generally lie about the plant and store semiconductor wafers waiting to be processed. Each material stocker typically services two or more bays and can hold hundreds of cassettes. The wafers are usually stored in cassettes in groups of about 25 wafers. The wafers are then disposed within a carrier and move from one process to another in the carrier. The carriers are usually tracked by their carrier code by a computer system as they move through the plant.
Once a wafer lot has been retrieved, and the equipment has been set up, the operation on the wafers by a particular piece of equipment, or xe2x80x9ctool,xe2x80x9d can begin. At this point, the lot is xe2x80x9cmoved-inxe2x80x9d to the operation. An operator on the line then communicates this information to the host computer. The wafer lot remains in this state until the operation is completed. Once the operation is completed, the operator must perform tests and verifications on the wafers. When all tests and verifications have been performed, the host computer application program must be notified. Wafers may have moved from one cassette to another as a result of the operation; therefore the host application and computer have to be notified of these moves. The operator then places the cassette of xe2x80x9cmoved-outxe2x80x9d wafers in the material stocker to await orders as to the location of the next piece of equipment that will perform operations on the wafers.
The semiconductor fabrication plant, including the bays, material stockers and the interconnecting path, typically operates under control of a distributed computer system running a factory management program. In this environment, the automated material handling system (AMHS) may conceptually include the cassettes, the transportation system (e.g., paths) and a control system (e.g., the distributed computer system). However, some of the key processes necessary to ensure that the line is operating properly, such as metrology, are usually located at a distance from where the wafers are currently being processed. It is necessary then to remove the wafers from the current processing tool and transport them back to the metrology area for measurements. This approach increases the number of times that the wafers are handled and increases cycle time in wafer processing.
The present invention is directed to addressing the above and other needs in connection with improving wafer processing tool flexibility and in reducing cycle time as wafers move through the semiconductor plant.
According to one aspect of the invention, it has been discovered that wafer processing lines are reconfigurable to accommodate changes in wafer processing recipes or to reduce wafer handling in a cluster tool of a wafer processing system. It has also been discovered that wafers are processed faster by moving the metrology and sorting processes/functions closer to the main wafer processing tools.
According to one aspect of the invention, a method of configuring wafer processing equipment in a semiconductor processing plant having a material handling system is described. A plurality of wafer processing tools is provided that are adapted to process at least one wafer presented by the material handling system. A retrofitable tool or multi-tool adapter is then provided that is adapted to be integrated with at least one of the plurality of processing tools. The retrofitable tool includes a wafer transfer unit disposed thereon to facilitate the transfer of at least one wafer between the processing tools and the retrofitable tool. The retrofitable tool is then coupled to at least one of the plurality of processing tools so as to reconfigure the wafer processing line as a function of a wafer processing recipe.
According to another aspect of the invention, a retrofitable tool for configuring wafer processing equipment in a semiconductor processing plant is disclosed. The retrofitable tool is adapted to operate in a semiconductor processing plant that includes a material handling system and at least one processing tool. The retrofitable tool is composed of an enclosure that includes a storage unit adapted to hold at least one wafer. A coupler arrangement is disposed on one side of the enclosure and is adapted to couple the retrofitable tool to at least one processing tool. An input port is disposed on the enclosure and a wafer transfer unit is coupled to the storage unit to facilitate the transfer of at least one wafer between the processing tool and the enclosure.
In yet another aspect of the invention, a system for configuring wafer processing equipment in a semiconductor processing plant includes a first processing tool and a second processing tool adapted to process at least one wafer. The system also includes a retrofitable tool adapted to be temporarily integrated with the first and second processing tool. A coupling arrangement is disposed on the retrofitable tool and on the processing tools to enable the retrofitable tool to be coupled with at least one of the first and second processing tools.
The above summary of the present invention is not intended to describe each illustrated embodiment or every implementation of the present invention. The figures in the detailed description that follow more particularly exemplify these embodiments.